说在前面

本次开始进行rocketmq源码解析，比较喜欢rocketmq的架构设计，rocketmq内嵌了namesrv注册中心保存了元数据，进行负载均衡、容错的一些处理，4.3以上支持消息事务，有管理控制台、命令行工具，底层namesrv与broker、client与server交互netty实现。更多精彩文章请关注“天河聊架构”微信公众号。

源码解析

创建NamesrvController，进入这个方法org.apache.rocketmq.namesrv.NamesrvStartup#main，再进入这个方法org.apache.rocketmq.namesrv.NamesrvStartup#main0

public static NamesrvController main0(String[] args) {

        try {
//            源码解析之创建namesrv控制器 =》
            NamesrvController controller = createNamesrvController(args);
//            源码解析之启动namesrv控制器 =》
            start(controller);
            String tip = "The Name Server boot success. serializeType=" + RemotingCommand.getSerializeTypeConfigInThisServer();
            log.info(tip);
            System.out.printf("%s%n", tip);
            return controller;
        } catch (Throwable e) {
            e.printStackTrace();
            System.exit(-1);
        }

        return null;
    }

进入这个方法org.apache.rocketmq.namesrv.NamesrvStartup#createNamesrvController

public static NamesrvController createNamesrvController(String[] args) throws IOException, JoranException {
//        从系统文件中查询rocketmq版本，默认4.3.0
        System.setProperty(RemotingCommand.REMOTING_VERSION_KEY, Integer.toString(MQVersion.CURRENT_VERSION));
//        PackageConflictDetect.detectFastjson();
//        构建命令行操作的指令 =》
        Options options = ServerUtil.buildCommandlineOptions(new Options());
//        mqnamesrv 启动namesrv命令 =》
        commandLine = ServerUtil.parseCmdLine("mqnamesrv", args, buildCommandlineOptions(options), new PosixParser());
        if (null == commandLine) {
//            系统非正常退出，流程结束
            System.exit(-1);
            return null;
        }

//        解析配置文件 =》
        final NamesrvConfig namesrvConfig = new NamesrvConfig();
//        =》
        final NettyServerConfig nettyServerConfig = new NettyServerConfig();
//        设置 namesrv的服务端口
        nettyServerConfig.setListenPort(9876);
//        c 指定启动的时候加载配置文件
        if (commandLine.hasOption('c')) {
//            命令行启动指定配置文件，前面用c开头
            String file = commandLine.getOptionValue('c');
            if (file != null) {
                InputStream in = new BufferedInputStream(new FileInputStream(file));
                properties = new Properties();
                properties.load(in);
                MixAll.properties2Object(properties, namesrvConfig);
                MixAll.properties2Object(properties, nettyServerConfig);
//                设置命令行启动namesrv指定的配置文件路径
                namesrvConfig.setConfigStorePath(file);
                System.out.printf("load config properties file OK, %s%n", file);
                in.close();
            }
        }

//        打印namesrv的配置信息，命令行上面加p
        if (commandLine.hasOption('p')) {
            MixAll.printObjectProperties(null, namesrvConfig);
            MixAll.printObjectProperties(null, nettyServerConfig);
//            正常程序退出
            System.exit(0);
        }

//        把命令行属性解析成properties
        MixAll.properties2Object(ServerUtil.commandLine2Properties(commandLine), namesrvConfig);
//        解析 ROCKETMQ_HOME 环境变量
        if (null == namesrvConfig.getRocketmqHome()) {
            System.out.printf("Please set the %s variable in your environment to match the location of the RocketMQ installation%n", MixAll.ROCKETMQ_HOME_ENV);
//            系统非正常退出
            System.exit(-2);
        }

        LoggerContext lc = (LoggerContext) LoggerFactory.getILoggerFactory();
        JoranConfigurator configurator = new JoranConfigurator();
        configurator.setContext(lc);
        lc.reset();
//        logback日志文件路径
        configurator.doConfigure(namesrvConfig.getRocketmqHome() + "/conf/logback_namesrv.xml");
        log = InternalLoggerFactory.getLogger(LoggerName.NAMESRV_LOGGER_NAME);
        MixAll.printObjectProperties(log, namesrvConfig);
        MixAll.printObjectProperties(log, nettyServerConfig);
//        创建namesrv控制器 =》
        final NamesrvController controller = new NamesrvController(namesrvConfig, nettyServerConfig);
        // remember all configs to prevent discard 把配置文件配置值的属性值注册到namesrv控制器
        controller.getConfiguration().registerConfig(properties);
        return controller;
    }

进入这个方法org.apache.rocketmq.srvutil.ServerUtil#buildCommandlineOptions 这里可以看到启动rocketmq的时候namesrv参数怎么制定

public static Options buildCommandlineOptions(final Options options) {
        Option opt = new Option("h", "help", false, "Print help");
        opt.setRequired(false);
        options.addOption(opt);
//        这里可以看到启动的时候有一个n参数指定namesrv的地址，可以是单机可以是集群，启动地址之间用;分开
        opt =
            new Option("n", "namesrvAddr", true,
                "Name server address list, eg: 192.168.0.1:9876;192.168.0.2:9876");
        opt.setRequired(false);
        options.addOption(opt);
        return options;
    }

在此我向大家推荐一个Java群 ：219571750
 里面会分享一些资深架构师录制的视频录像：
（有Spring，MyBatis，Netty源码分析，高并发、高性能、分布式、微服务架构的原理，JVM性能优化、分布式架构、面试资料）
等这些成为架构师必备的知识体系 进群马上免费领取，目前受益良多！

进入这个方法org.apache.rocketmq.namesrv.NamesrvStartup#buildCommandlineOptions 从这里看出来启动rocketmq的时候怎么指定配置文件，是否自动创建topic、消费组这些参数都可以在配置文件中配置

//    指定namesrv启动的时候加载的配置文件
    public static Options buildCommandlineOptions(final Options options) {
        Option opt = new Option("c", "configFile", true, "Name server config properties file");
        opt.setRequired(false);
        options.addOption(opt);
//        控制台输出配置项
        opt = new Option("p", "printConfigItem", false, "Print all config item");
        opt.setRequired(false);
        options.addOption(opt);
        return options;
    }

从这里可以看到一些配置的存储地址

public class NamesrvConfig {
    private static final InternalLogger log = InternalLoggerFactory.getLogger(LoggerName.NAMESRV_LOGGER_NAME);
//    解析ROCKETMQ_HOME
    private String rocketmqHome = System.getProperty(MixAll.ROCKETMQ_HOME_PROPERTY, System.getenv(MixAll.ROCKETMQ_HOME_ENV));
//    kvConfig存储地址
    private String kvConfigPath = System.getProperty("user.home") + File.separator + "namesrv" + File.separator + "kvConfig.json";
//    namesrv存储地址
    private String configStorePath = System.getProperty("user.home") + File.separator + "namesrv" + File.separator + "namesrv.properties";
nettyserver的一些配置

public class NettyServerConfig implements Cloneable {
//    netty server监听端口
    private int listenPort = 8888;
//    服务端工作线程数
    private int serverWorkerThreads = 8;
//    服务端回调执行线程
    private int serverCallbackExecutorThreads = 0;
//    服务端选择器线程
    private int serverSelectorThreads = 3;
//    oneway方式信号量的值
    private int serverOnewaySemaphoreValue = 256;
//    服务端异步信号量值
    private int serverAsyncSemaphoreValue = 64;
//    服务端channel最大空闲时间
    private int serverChannelMaxIdleTimeSeconds = 120;
//    发送消息最大大小从系统属性中获取，默认值65535
    private int serverSocketSndBufSize = NettySystemConfig.socketSndbufSize;
//    接受消息最大大小从系统属性中获取，默认值65535
    private int serverSocketRcvBufSize = NettySystemConfig.socketRcvbufSize;
    private boolean serverPooledByteBufAllocatorEnable = true;
nettyserver默认监听端口9876

nettyServerConfig.setListenPort(9876);

从这里可以看到是解析启动的时候指定的配置文件属性

//        c 指定启动的时候加载配置文件
        if (commandLine.hasOption('c')) {
//            命令行启动指定配置文件，前面用c开头
            String file = commandLine.getOptionValue('c');
            if (file != null) {
                InputStream in = new BufferedInputStream(new FileInputStream(file));
                properties = new Properties();
                properties.load(in);
                MixAll.properties2Object(properties, namesrvConfig);
                MixAll.properties2Object(properties, nettyServerConfig);

配置文件中可以配置这个类org.apache.rocketmq.common.namesrv.NamesrvConfig namesrv的一些配置

//    解析ROCKETMQ_HOME
    private String rocketmqHome = System.getProperty(MixAll.ROCKETMQ_HOME_PROPERTY, System.getenv(MixAll.ROCKETMQ_HOME_ENV));
//    kvConfig存储地址
    private String kvConfigPath = System.getProperty("user.home") + File.separator + "namesrv" + File.separator + "kvConfig.json";
//    namesrv存储地址
    private String configStorePath = System.getProperty("user.home") + File.separator + "namesrv" + File.separator + "namesrv.properties";
    private String productEnvName = "center";
    private boolean clusterTest = false;
    private boolean orderMessageEnable = false;

也可以配置这个类org.apache.rocketmq.remoting.netty.NettyServerConfig nettyserver的一些配置

public class NettyServerConfig implements Cloneable {
//    netty server监听端口
    private int listenPort = 8888;
//    服务端工作线程数
    private int serverWorkerThreads = 8;
//    服务端回调执行线程
    private int serverCallbackExecutorThreads = 0;
//    服务端选择器线程
    private int serverSelectorThreads = 3;
//    oneway方式信号量的值
    private int serverOnewaySemaphoreValue = 256;
//    服务端异步信号量值
    private int serverAsyncSemaphoreValue = 64;
//    服务端channel最大空闲时间
    private int serverChannelMaxIdleTimeSeconds = 120;
//    发送消息最大大小从系统属性中获取，默认值65535
    private int serverSocketSndBufSize = NettySystemConfig.socketSndbufSize;
//    接受消息最大大小从系统属性中获取，默认值65535
    private int serverSocketRcvBufSize = NettySystemConfig.socketRcvbufSize;
    private boolean serverPooledByteBufAllocatorEnable = true;

namesrv配置的存储地址就是启动指定的配置文件

namesrvConfig.setConfigStorePath(file);

也可以在命令行上指定namesrv属性配置

MixAll.properties2Object(ServerUtil.commandLine2Properties(commandLine), namesrvConfig);
logback的配置文件

configurator.doConfigure(namesrvConfig.getRocketmqHome() + "/conf/logback_namesrv.xml");
根据namesrv配置和nettyserver配置创建NamesrvController

final NamesrvController controller = new NamesrvController(namesrvConfig, nettyServerConfig);
进入这个方法org.apache.rocketmq.namesrv.NamesrvController#NamesrvController

public NamesrvController(NamesrvConfig namesrvConfig, NettyServerConfig nettyServerConfig) {
        this.namesrvConfig = namesrvConfig;
        this.nettyServerConfig = nettyServerConfig;
        this.kvConfigManager = new KVConfigManager(this);
        this.routeInfoManager = new RouteInfoManager();
        this.brokerHousekeepingService = new BrokerHousekeepingService(this);
//        =》
        this.configuration = new Configuration(
            log,
            this.namesrvConfig, this.nettyServerConfig
        );
//        指定保存namesrv配置的配置文件
        this.configuration.setStorePathFromConfig(this.namesrvConfig, "configStorePath");
    }

进入这里org.apache.rocketmq.namesrv.routeinfo.RouteInfoManager#RouteInfoManager

public RouteInfoManager() {
//        指定长度，减少扩容提高性能
        this.topicQueueTable = new HashMap<String, List<QueueData>>(1024);//topicQueue缓存信息
        this.brokerAddrTable = new HashMap<String, BrokerData>(128);//broker地址缓存
        this.clusterAddrTable = new HashMap<String, Set<String>>(32);//集群地址缓存
        this.brokerLiveTable = new HashMap<String, BrokerLiveInfo>(256);//可用的broker缓存
        this.filterServerTable = new HashMap<String, List<String>>(256);//过滤的server地址
    }
设置namrsrv配置存储地址System.getProperty("user.home") + File.separator + "namesrv" + File.separator + "namesrv.properties"

this.configuration.setStorePathFromConfig(this.namesrvConfig, "configStorePath");
// remember all configs to prevent discard 把配置文件配置值的属性值注册到namesrv控制器
controller.getConfiguration().registerConfig(properties);

进入这个方法
org.apache.rocketmq.common.Configuration#registerConfig(java.util.Properties)

public Configuration registerConfig(Object configObject) {
    try {
        readWriteLock.writeLock().lockInterruptibly();
        try {

            Properties registerProps = MixAll.object2Properties(configObject);
            merge(registerProps, this.allConfigs);
            configObjectList.add(configObject);
        } finally {
            readWriteLock.writeLock().unlock();
        }
    } catch (InterruptedException e) {
        log.error("registerConfig lock error");
    }
    return this;
}
/**
 * All properties include configs in object and extend properties.
 * 所有的启动配置都在这里
 */
private Properties allConfigs = new Properties();